Photographic apparatus

ABSTRACT

A photographic apparatus comprises a movable platform, an acceleration sensor, and a controller. 
     The movable platform has an imager that captures an optical image, and is movable and rotatable in an xy plane. The acceleration sensor detects a first gravitational component and a second gravitational component. The first gravitational component is the component of gravitational acceleration in the x direction. The second gravitational component is the component of gravitational acceleration in the y direction. The controller specifies a holding state of the photographic apparatus, calculates an inclination angle formed by rotation of the photographic apparatus, as measured with respect to a level plane, on the basis of the first and second gravitational components, and performs a movement control of the movable platform for an inclination correction based on the inclination angle. The controller specifies the holding state before an imaging operation, and performs the inclination correction during the imaging operation.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photographic apparatus, and inparticular, to a photographic apparatus that performs an inclinationcorrection.

2. Description of the Related Art

There is known a type of image stabilization (also known as anti-shake,but hereinafter, simply “stabilization”) apparatus for a photographicapparatus. The image stabilization apparatus corrects for the effects ofhand shake by moving a movable platform including an image stabilizationlens or by moving an imager (an imaging sensor) in an xy planeperpendicular to an optical axis of a taking lens of the photographicapparatus, in accordance with the amount of hand shake that occursduring the imaging process.

Japanese unexamined patent publication (KOKAI) No. 2006-71743 disclosesan image stabilization apparatus that calculates hand-shake quantity onthe basis of hand shake due to yaw, pitch, and roll, and then performs astabilization on the basis of the hand-shake quantity (the first,second, and third hand-shake angles).

In this stabilization operation, the following stabilization functionsare performed: a first stabilization that corrects the hand shake causedby yaw, a second stabilization that corrects the hand shake caused bypitch, and a third stabilization that corrects the hand shake caused byroll.

In the third stabilization, the rotation angle (hand shake displacementangle) of the photographic apparatus is calculated from the point whenthe third stabilization commences. However, the inclination angle of thephotographic apparatus, formed by rotation of the photographic apparatusaround its optical axis, as measured with respect to a level plane, isnot considered. The inclination angle changes according to theorientation of the photographic apparatus.

If the photographic apparatus is inclined when the stabilizationcommences, the third stabilization is performed so as to keep thisinclined state. Therefore, the inclination correction in order to levelis not performed so that each of the four sides of the rectanglecomposing the outline of the imaging surface of the imager is notparallel to either the x direction or the y direction, in other words,the image is captured with the imager being inclined.

SUMMARY OF THE INVENTION

Therefore, an object of the present invention is to provide aphotographic apparatus that performs the inclination correction.

According to the present invention, a photographic apparatus comprises amovable platform, an acceleration sensor, and a controller.

The movable platform has an imager that captures an optical imagethrough a taking lens, and is movable and rotatable in an xy planeperpendicular to an optical axis of the taking lens.

The acceleration sensor detects a first gravitational component and asecond gravitational component. The first gravitational component is thecomponent of gravitational acceleration in the x direction perpendicularto the optical axis. The second gravitational component is the componentof gravitational acceleration in the y direction perpendicular to theoptical axis and the x direction.

The controller specifies a holding state of the photographic apparatus,calculates an inclination angle of the photographic apparatus formed byrotation of the photographic apparatus around the optical axis, asmeasured with respect to a level plane perpendicular to the direction ofgravitational force, on the basis of the first gravitational componentand the second gravitational component, and performs a movement controlof the movable platform for an inclination correction based on theinclination angle.

The controller specifies the holding state before an imaging operationby the imager that commences when a shutter release switch is set to theON state, and performs the inclination correction during the imagingoperation.

BRIEF DESCRIPTION OF THE DRAWINGS

The objects and advantages of the present invention will be betterunderstood from the following description, with reference to theaccompanying drawings in which:

FIG. 1 is a perspective view of the embodiment of the photographicapparatus as viewed from the rear;

FIG. 2 is a front view of the photographic apparatus, when thephotographic apparatus is held in the first horizontal orientation;

FIG. 3 is a circuit construction diagram of the photographic apparatus;

FIG. 4 is a flowchart that shows the main operation of the photographicapparatus;

FIG. 5 is a flowchart that shows the details of the timer interruptprocess;

FIG. 6 illustrates the calculations involved in the stabilization andinclination correction;

FIG. 7 is a construction diagram of the movable platform;

FIG. 8 is a flowchart showing the details of the calculation of thethird digital displacement angle;

FIG. 9 is a front view of the photographic apparatus, when thephotographic apparatus is held in the second horizontal orientation;

FIG. 10 is a front view of the photographic apparatus, when thephotographic apparatus is held in the first vertical orientation;

FIG. 11 is a front view of the photographic apparatus, when thephotographic apparatus is held in the second vertical orientation;

FIG. 12 is a front view of the photographic apparatus, and Kθ_(n) is theangle formed when the photographic apparatus is rotated (inclined) in acounter-clockwise direction as viewed from the front, away from thefirst horizontal orientation;

FIG. 13 is a front view of the photographic apparatus, and Kθ_(n) is theangle formed when the photographic apparatus is rotated (inclined) in acounter-clockwise direction as viewed from the front, away from thefirst vertical orientation;

FIG. 14 is a front view of the photographic apparatus, and Kθ_(n) is theangle formed when the photographic apparatus is rotated (inclined) in acounter-clockwise direction as viewed from the front, away from thesecond horizontal orientation;

FIG. 15 is a front view of the photographic apparatus, and Kθ_(n) is theangle formed when the photographic apparatus is rotated (inclined) in acounter-clockwise direction as viewed from the front, away from thesecond vertical orientation;

FIG. 16 shows the first and second angle ranges; and

FIG. 17 is a flowchart showing the details of the calculation of theholding state parameter.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is described below with reference to theembodiment shown in the drawings. In the embodiment, the photographicapparatus 1 is a digital camera. A camera lens (i.e. taking lens) 67 ofthe photographic apparatus 1 has the optical axis LX.

By way of orientation in the embodiment, the x direction, the ydirection, and the z direction are defined (see FIG. 1). The x directionis the direction perpendicular to the optical axis LX. The y directionis the direction perpendicular to the optical axis LX and the xdirection. The z direction is the direction parallel to the optical axisLX and perpendicular to both the x direction and the y direction.

The relationships between the direction of gravitational force and the xdirection, the y direction, and the z direction, change according to theorientation of the photographic apparatus 1.

For example, when the photographic apparatus 1 is held in the firsthorizontal orientation, in other words, when the photographic apparatus1 is held horizontally and the upper surface of the photographicapparatus 1 faces upward (see FIG. 2), the x direction and the zdirection are perpendicular to the direction of gravitational force andthe y direction is parallel to the direction of gravitational force.

When the photographic apparatus 1 is held in the second horizontalorientation, in other words, when the photographic apparatus 1 is heldhorizontally and the lower surface of the photographic apparatus 1 facesupward (see FIG. 9), the x direction and the z direction areperpendicular to the direction of gravitational force and the ydirection is parallel to the direction of gravitational force.

When the photographic apparatus 1 is held in the first verticalorientation, in other words, when the photographic apparatus 1 is heldvertically and one of the side surfaces of the photographic apparatus 1faces upward (see FIG. 10), the x direction is parallel to the directionof gravitational force and the y direction and the z direction areperpendicular to the direction of gravitational force.

When the photographic apparatus 1 is held in the second verticalorientation, in other words, when the photographic apparatus 1 is heldvertically and the other side surface of the photographic apparatus 1faces upward (see FIG. 11), the x direction is parallel to the directionof gravitational force and the y direction and the z direction areperpendicular to the direction of gravitational force.

When the front surface of the photographic apparatus 1 faces in thedirection of gravitational force, the x direction and the y directionare perpendicular to the direction of gravitational force and the zdirection is parallel to the direction of gravitational force. The frontsurface of the photographic apparatus 1 is the side on which camera lens67 is attached.

The imaging part of the photographic apparatus 1 comprises a PON button11, a PON switch 11 a, a photometric switch 12 a, a shutter releasebutton 13, a shutter release switch 13 a for an exposure operation, acorrection button 14, a correction switch 14 a, a display 17 such as anLCD monitor or the like, a mirror-aperture-shutter unit 18, a DSP 19, aCPU 21, an AE (automatic exposure) unit 23, an AF (automatic focus) unit24, an imaging unit 39 a in the correction unit 30, and the camera lens67 (see FIGS. 1, 2, and 3).

Whether the PON switch 11 a is in the ON state or OFF state isdetermined by the state of the PON button 11. The ON/OFF states of thephotographic apparatus 1 correspond to the ON/OFF states of the PONswitch 11 a.

The subject image is captured as an optical image through the cameralens 67 by the imaging unit 39 a, and the captured image is displayed onthe display 17. The subject image can be optically observed through theoptical finder (not depicted).

When the shutter release button 13 is partially depressed by theoperator, the photometric switch 12 a changes to the ON state so thatthe photometric operation, the AF sensing operation, and the focusingoperation are performed.

When the shutter release button 13 is fully depressed by the operator,the shutter release switch 13 a changes to the ON state so that theimaging operation by the imaging unit 39 a (the imaging apparatus) isperformed, and the captured image is stored.

The CPU 21 performs a release-sequence operation including the imagingoperation after the shutter release switch 13 a is set to the ON state.

The mirror-aperture-shutter unit 18 is connected to port P7 of the CPU21 and performs an UP/DOWN operation of the mirror (a mirror-upoperation and a mirror-down operation), an OPEN/CLOSE operation of theaperture, and an OPEN/CLOSE operation of the shutter corresponding tothe ON state of the shutter release switch 13 a.

The camera lens 67 is an interchangeable lens of the photographicapparatus 1 and is connected to port P8 of the CPU 21. The camera lens67 outputs the lens information including the lens coefficient F etc.,stored in a built-in ROM in the camera lens 67, to the CPU 21, when thephotometric operation is performed.

The DSP 19 is connected to port P9 of the CPU 21 and to the imaging unit39 a. Based on a command from the CPU 21, the DSP 19 performs thecalculation operations, such as the image-processing operation, etc., onthe image signal obtained by the imaging operation of the imaging unit39 a.

The CPU 21 is a control apparatus that controls each part of thephotographic apparatus 1 in its imaging operation, and in itsstabilization (i.e. anti-shake) and inclination correction.

The stabilization and inclination correction includes both the movementcontrol of the movable platform 30 a and position-detection efforts.

In the embodiment, the stabilization includes a first stabilization thatmoves the movable platform 30 a in the x direction and a secondstabilization that moves the movable platform 30 a in the y direction.

Furthermore, the CPU 21 stores the value of the correction parameter SRthat indicates whether the photographic apparatus 1 is in the correctionmode or not, the value of the release-state parameter RP, the value ofthe mirror state parameter MP, and the value of the holding stateparameter SIS.

The value of the release-state parameter RP changes with respect to therelease-sequence operation. When the release-sequence operation isperformed, the value of the release-state parameter RP is set to 1 (seesteps S21 to S28 in FIG. 4), otherwise, the value of the release-stateparameter RP is set (reset) to 0 (see steps S13 and S28 in FIG. 4).

While the mirror-up operation is performed before the exposure operationfor the imaging operation, the value of the mirror state parameter MP isset to 1 (see step S22 in FIG. 4); otherwise, the value of the mirrorstate parameter MP is set to 0 (see step S24 in FIG. 4).

Whether the mirror-up operation of the photographic apparatus 1 isfinished is determined by the detection of the ON/OFF states of amechanical switch (not depicted). Whether the mirror-down operation ofthe photographic apparatus 1 is finished is determined by the detectionof the completion of the shutter charge.

The holding state parameter SIS is the parameter whose value changes inaccordance with the holding state of the photographic apparatus 1.

Specifically, when the photographic apparatus 1 is held approximately inthe first horizontal orientation as shown in FIG. 2, the value of theholding state parameter SIS is set to 0 (SIS=0). When the photographicapparatus 1 is held approximately in the second horizontal orientationas shown in FIG. 9, the value of the holding state parameter SIS is setto 1 (SIS=1). When the photographic apparatus 1 is held approximately inthe first vertical orientation as shown in FIG. 10, the value of theholding state parameter SIS is set to 2 (SIS=2). When the photographicapparatus 1 is held approximately in the second vertical orientation asshown in FIG. 11, the value of the holding state parameter SIS is set to3 (SIS=3).

The holding state parameter SIS is used for the photometric operation(see step S18 in FIG. 4), the AF sensing operation (see step S19 in FIG.4), and storing the image, on which the image-processing operation isperformed, in the memory of the photographic apparatus 1 (see step S30in FIG. 4).

Specifically, selecting and weighting of the photometric area areperformed in accordance with the holding state of the photographicapparatus 1, in the photometric operation.

Furthermore, selecting and weighting of the AF sensing area areperformed in accordance with the holding state of the photographicapparatus 1, in the AF sensing operation.

Information indicating that the photographic apparatus 1 is heldapproximately in which one of either the first horizontal orientation,the second horizontal orientation, the first vertical orientation, orthe second vertical orientation, is attached to the header etc., of thefile of the image that is stored in the memory.

Furthermore, the CPU 21 stores the values of the first digital angularvelocity signal Vx_(n), the second digital angular velocity signalVy_(n), the first digital angular velocity VVx_(n), the second digitalangular velocity VVy_(n), the first digital acceleration signal Dah_(n),the second digital acceleration signal Dav_(n), the first digitalacceleration Aah_(n), the second digital acceleration Aav_(n), the firstdigital displacement angle Kθ_(n) (the hand-shake angle caused by yaw),the second digital displacement angle Ky_(n) (the hand-shake anglecaused by pitch), the third digital displacement angle Kθ_(n) (theinclination angle of the photographic apparatus 1), the horizontaldirection component of the position S_(n), Sx_(n), the verticaldirection component of the position S_(n), Sy_(n), the rotationaldirection component (the inclination angle) of the position S_(n),Sθ_(n), the first vertical direction component of the first drivingpoint, Syl_(n), the second vertical direction component of the seconddriving point, Syr_(n), the horizontal driving force Dx_(n), the firstvertical driving force Dyl_(n), the second vertical driving forceDyr_(n), the horizontal direction component of the position P_(n) afterA/D conversion, pdx_(n), the first vertical direction component of theposition P_(n) after A/D conversion, pdyl_(n), the second verticaldirection component of the position P_(n) after A/D conversion,pdyr_(n), the lens coefficient F, and the hall sensor distancecoefficient HSD. The hall sensor distance coefficient HSD is therelative distance between the first vertical hall sensor hv1 and thesecond vertical hall sensor hv2 in the x direction of the initial state(see FIG. 7).

In the initial state, the movable platform 30 a is positioned at thecenter of its movement range in both the x and y directions, and each ofthe four sides of the rectangle composing the outline of the imagingsurface of the imager (an imaging sensor) 39 a 1 is parallel to eitherthe x direction or the y direction.

The AE unit (exposure-calculating unit) 23 performs the photometricoperation and calculates photometric values based on the subject beingphotographed. The AE unit 23 also calculates the aperture value and theduration of the exposure operation, with respect to the photometricvalues, both of which are needed for the imaging operation. The AF unit24 performs the AF sensing operation and the corresponding focusingoperation, both of which are needed for the imaging operation. In thefocusing operation, the camera lens 67 is re-positioned along theoptical axis LX.

The stabilization and inclination correction part (the stabilization andinclination correction apparatus) of the photographic apparatus 1comprises a correction button 14, a correction switch 14 a, a display17, a CPU 21, a detection unit 25, a driver circuit 29, a correctionunit 30, a hall-sensor signal-processing unit 45, and the camera lens67.

The ON/OFF states of the correction switch 14 a change according to theoperation state of the correction button 14.

Specifically, when the correction button 14 is depressed by theoperator, the correction switch 14 a is changed to the ON state so thatthe stabilization (the translational movement) and inclinationcorrection, in which the detection unit 25 and the correction unit 30are driven independently of the other operations which include thephotometric operation etc., is carried out at the predetermined timeinterval. When the correction switch 14 a is in the ON state, (in otherwords in the correction mode), the correction parameter SR is set to 1(SR=1). When the correction switch 14 a is not in the ON state, (inother words in the non-correction mode), the correction parameter SR isset to 0 (SR=0). In the embodiment, the value of the predetermined timeinterval is set to 1 ms.

The various output commands corresponding to the input signals of theseswitches are controlled by the CPU 21.

The information indicating whether the photometric switch 12 a is in theON state or OFF state is input to port P12 of the CPU 21 as a 1-bitdigital signal. The information indicating whether the shutter releaseswitch 13 a is in the ON or OFF state is input to port P13 of the CPU 21as a 1-bit digital signal. Likewise, the information indicating whetherthe correction switch 14 a is in the ON or OFF state is input to portP14 of the CPU 21 as a 1-bit digital signal.

The AE unit 23 is connected to port P4 of the CPU 21 for inputting andoutputting signals. The AF unit 24 is connected to port P5 of the CPU 21for inputting and outputting signals. The display 17 is connected toport P6 of the CPU 21 for inputting and outputting signals.

Next, the details of the input and output relationships between the CPU21 and the detection unit 25, the driver circuit 29, the correction unit30, and the hall-sensor signal-processing unit 45 are explained.

The detection unit 25 has a first angular velocity sensor 26 a, a secondangular velocity sensor 26 b, an acceleration sensor 26 c, a firsthigh-pass filter circuit 27 a, a second high-pass filter circuit 27 b, afirst amplifier 28 a, a second amplifier 28 b, a third amplifier 28 c,and a fourth amplifier 28 d.

The first angular velocity sensor 26 a detects the angular velocity ofrotary motion of the photographic apparatus 1 around the axis of the ydirection (the yaw). In other words, the first angular velocity sensor26 a is a gyro sensor that detects the yaw angular velocity.

The second angular velocity sensor 26 b detects the angular velocity ofrotary motion of the photographic apparatus 1 around the axis of the xdirection (the pitch). In other words, the second angular velocitysensor 26 b is a gyro sensor that detects the pitch angular velocity.

The acceleration sensor 26 c detects a first gravitational component anda second gravitational component. The first gravitational component isthe horizontal component of gravitational acceleration in the xdirection. The second gravitational component is the vertical componentof gravitational acceleration in the y direction.

The first high-pass filter circuit 27 a reduces the low-frequencycomponent of the signal output from the first angular velocity sensor 26a, because the low-frequency component of the signal output from thefirst angular velocity sensor 26 a includes signal elements that arebased on null voltage and panning motion, neither of which are relatedto hand shake.

Similarly, the second high-pass filter circuit 27 b reduces thelow-frequency component of the signal output from the second angularvelocity sensor 26 b, because the low-frequency component of the signaloutput from the second angular velocity sensor 26 b includes signalelements that are based on null voltage and panning motion, neither ofwhich are related to hand shake.

The first amplifier 28 a amplifies the signal representing the yawangular velocity, whose low-frequency component has been reduced, andoutputs the analog signal to the A/D converter A/D 0 of the CPU 21 as afirst angular velocity vx.

The second amplifier 28 b amplifies the signal representing the pitchangular velocity, whose low-frequency component has been reduced, andoutputs the analog signal to the A/D converter A/D 1 of the CPU 21 as asecond angular velocity vy.

The third amplifier 28 c amplifies the signal representing the firstgravitational component output from the acceleration sensor 26 c, andoutputs the analog signal to the A/D converter A/D 2 of the CPU 21 as afirst acceleration ah.

The fourth amplifier 28 d amplifies the signal representing the secondgravitational component output from the acceleration sensor 26 c, andoutputs the analog signal to the A/D converter A/D 3 of the CPU 21 as asecond acceleration av.

The third and fourth amplifiers 28 c and 28 d are connected to port P10of the CPU 21. The amplification rate of the third and fourth amplifiers28 c and 28 d are set on the basis of the output signal from port P10 ofthe CPU 21.

Specifically, the Hi signal is output to the third and fourth amplifiers28 c and 28 d, in order to amplify the signal representing the first andsecond gravitational components with the low amplification rate Am2, andto calculate the holding state parameter SIS, until the release sequenceoperation commences.

The Lo signal is output to the third and fourth amplifiers 28 c and 28d, in order to amplify the signal representing the first and secondgravitational components with the high amplification rate Am1, and toperform the inclination correction, during the release sequenceoperation.

In the inclination correction, the movable platform 30 a is rotatedwithin the movement range, but cannot be rotated beyond the movementrange.

An angular range within which the inclination correction can beperformed is defined as a first angle range θ_(inc).

An output range of the signal representing the first and secondgravitational components corresponding to the first angle range θ_(inc)is defined as a first output range W1.

On the other hand, in the calculation of the holding state parameterSIS, it is necessary to consider the any type of the envisioned holdingstates of the photographic apparatus 1.

An angular range within which the inclination angle has to be detectedfor calculating the holding state parameter SIS is defined as a secondangle range θ_(dec) (=90 degrees).

An output range of the signal representing the first and secondgravitational components corresponding to the second angle range θ_(dec)is defined as a second output range W2.

The first angle range θ_(inc) is narrower than the second angle rangeθ_(dec) (θ_(inc)<θ_(dec), see FIG. 16).

Therefore, the first output range W1 is narrower than the second outputrange W2.

In the inclination correction, it is necessary to calculate theinclination angle (third digital displacement angle Kθ_(n)) accurately,in order to level the inclined movable platform 30 a. Namely, it isnecessary to obtain the first and second accelerations ah and av with ahigh degree of accuracy.

On the other hand, in the calculation of the holding state parameterSIS, it is not necessary to calculate the inclination angle accurately,because the holding state parameter SIS is selected from the fournumbers 0 to 3 corresponding to the orientation of the photographicapparatus 1.

In the inclination correction, the amplification for the signalrepresenting the first and second gravitational components with the highamplification rate Am1 is performed by the third and fourth amplifiers28 c and 28 d, in order to widen the narrow first output range W1 untilit reaches the limit of the input range of the A/D converters A/D 2 andA/D 3 of the CPU 21 that the A/D conversion can be performed. Namely,the detection resolution of the A/D conversion in the A/D converters A/D2 and A/D 3 of the CPU 21 is increased. The high amplification rate Am1is higher than the low amplification rate Am2 (Am1>Am2).

On the other hand, in the calculation of the holding state parameterSIS, the amplification for the signal representing the first and secondgravitational components with the low amplification rate Am2 isperformed by the third and fourth amplifiers 28 c and 28 d, in order towiden the wide second output range W2 until it reaches the limit of theinput range of the A/D converters A/D 2 and A/D 3 of the CPU 21 that theA/D conversion can be performed. Namely, the detection resolution of theA/D conversion in the A/D converters A/D 2 and A/D 3 of the CPU 21 isdecreased compared to the detection resolution used in the inclinationcorrection.

Because the inclination correction is performed during the releasesequence operation and the calculation of the holding state parameterSIS is performed before the release sequence operation commences, thetiming of the inclination correction and the timing of the calculationof the holding state parameter SIS do not overlap. Therefore, a problemdoes not occur, even if the amplification rate of the third and fourthamplifiers 28 c and 28 d is changed in each of the inclinationcorrection and the calculation of the holding state parameter SIS.

The reduction of the low-frequency component is a two-step process. Theprimary part of the analog high-pass filtering is performed first by thefirst and second high-pass filter circuits 27 a and 27 b, followed bythe secondary part of the digital high-pass filtering that is performedby the CPU 21.

The cut-off frequency of the secondary part of the digital high-passfiltering is higher than that of the primary part of the analoghigh-pass filtering.

In the digital high-pass filtering, the value of a first high-passfilter time constant hx and a second high-pass filter time constant hycan be easily changed.

The supply of electric power to the CPU 21 and each part of thedetection unit 25 begins after the PON switch 11 a is set to the ONstate (i.e. when the main power supply is set to the ON state). Thecalculation of a hand-shake quantity (the digital displacement angleKx_(n) and the second digital displacement angle Ky_(n)) and aninclination angle (the third digital displacement angle Kθ_(n)) beginsafter the PON switch 11 a is set to the ON state.

The CPU 21 converts the first angular velocity vx, which is input to theA/D converter A/D 0, to a first digital angular velocity signal Vx_(n)(A/D conversion operation). It also calculates a first digital angularvelocity VVx_(n) by reducing the low-frequency component of the firstdigital angular velocity signal Vx_(n) (the digital high-pass filtering)because the low-frequency component of the first digital angularvelocity signal Vx_(n) includes signal elements that are based on nullvoltage and panning motion, neither of which are related to hand shake.It also calculates a first hand-shake quantity (a first hand-shakedisplacement angle around the y direction: a first digital displacementangle Kx_(n) caused by yaw) by integrating the first digital angularvelocity VVx_(n) (the integration), for the first stabilization.

Similarly, the CPU 21 converts the second angular velocity vy, which isinput to the A/D converter A/D 1, to a second digital angular velocitysignal Vy_(n) (A/D conversion operation). It also calculates a seconddigital angular velocity VVy_(n) by reducing the low-frequency componentof the second digital angular velocity signal Vy_(n) (the digitalhigh-pass filtering) because the low-frequency component of the seconddigital angular velocity signal Vy_(n) includes signal elements that arebased on null voltage and panning motion, neither of which are relatedto hand shake. It also calculates a second hand-shake quantity (a secondhand-shake displacement angle around the x direction: a second digitaldisplacement angle Ky_(n) caused by pitch) by integrating the seconddigital angular velocity VVy_(n) (the integration), for the secondstabilization.

Furthermore, the CPU 21 converts the first acceleration ah, which isinput to the A/D converter A/D 2, to a first digital acceleration signalDah_(n) (A/D conversion operation). It also calculates a first digitalacceleration Aah_(n) by reducing the high-frequency component of thefirst digital acceleration signal Dah_(n) (the digital low-passfiltering) in order to reduce the noise component in the first digitalacceleration signal Dah_(n).

Similarly, the CPU 21 converts the second acceleration av, which isinput to the A/D converter A/D 3, to a second digital accelerationsignal Dav_(n) (A/D conversion operation). It also calculates a seconddigital acceleration Aav_(n) by reducing the high-frequency component ofthe second digital acceleration signal Dav_(n) (the digital low-passfiltering) in order to reduce the noise component in the second digitalacceleration signal Dav_(n).

The CPU 21 also calculates the inclination angle (third digitaldisplacement angle Kθ_(n)) of the photographic apparatus 1, formed byrotation of the photographic apparatus 1 around its optical axis LX, asmeasured with respect to a level plane perpendicular to the direction ofgravitational force, on the basis of the magnitude relation between theabsolute value of the first digital acceleration Aah_(n) and theabsolute value of the second digital acceleration Aav_(n).

The inclination angle (the third digital displacement angle Kθ_(n)) ofthe photographic apparatus 1 changes according to the orientation of thephotographic apparatus 1 and is measured with respect to one of thefirst horizontal orientation, the second horizontal orientation, thefirst vertical orientation, and the second vertical orientation.Therefore, the inclination angle of the photographic apparatus 1 isrepresented by the angle at which the x direction or the y directionintersects a level plane.

When one of the x direction and the y direction intersects a level planeat an angle of 0 degrees, and when the other of the x direction and they direction intersects a level plane at an angle of 90 degrees, thephotographic apparatus 1 is in a non-inclined state.

Thus, the CPU 21 and the detection unit 25 have a function forcalculating the hand-shake quantity (the first and second hand-shakequantities) and the inclination angle.

The first digital acceleration Aah_(n) (the first gravitationalcomponent) and the second digital acceleration Aav_(n) (the secondgravitational component) change according to the orientation of thephotographic apparatus 1, and take values from −1 to +1.

For example, when the photographic apparatus 1 is held in the firsthorizontal orientation, in other words, when the photographic apparatus1 is held horizontally and the upper surface of the photographicapparatus 1 faces upward (see FIG. 2), the first digital accelerationAah_(n) is 0 and the second digital acceleration Aav_(n) is +1.

When the photographic apparatus 1 is held in the second horizontalorientation, in other words, when the photographic apparatus 1 is heldhorizontally and the lower surface of the photographic apparatus 1 facesupward (see FIG. 9), the first digital acceleration Aah_(n) is 0 and thesecond digital acceleration Aav_(n) is −1.

When the photographic apparatus 1 is held in the first verticalorientation, in other words, when the photographic apparatus 1 is heldvertically and one of the side surfaces of the photographic apparatus 1faces upward (see FIG. 10), the first digital acceleration Aah_(n) is +1and the second digital acceleration Aav_(n) is 0.

When the photographic apparatus 1 is held in the second verticalorientation, in other words, when the photographic apparatus 1 is heldvertically and the other side surface of the photographic apparatus 1faces upward (see FIG. 11), the first digital acceleration Aah_(n) is −1and the second digital acceleration Aav_(n) is 0.

When the front surface of the photographic apparatus 1 faces thedirection of gravitational force or the opposite direction, in otherwords, when the front surface of the photographic apparatus 1 facesupward or downward, the first digital acceleration Aah_(n) and thesecond digital acceleration Aav_(n) are 0.

When the photographic apparatus 1 is rotated (inclined) at an angleKθ_(n) in a counter-clockwise direction viewed from the front, from thefirst horizontal orientation (see FIG. 12), the first digitalacceleration Aah_(n) is +sin(Kθ_(n)) and the second digital accelerationAav_(n) is +cos(Kθ_(n)).

Therefore, the inclination angle (the third digital displacement angleKθ_(n)) can be calculated by performing an arcsine transformation on thefirst digital acceleration Aah_(n) or by performing an arccosinetransformation on the second digital acceleration Aav_(n).

However, while the absolute value of the inclination angle (the thirddigital displacement angle Kθ_(n)) is very small, in other words, nearly0, the variation of the sine function is larger than that of the cosinefunction so that the inclination angle is best calculated by using thearcsine transformation rather than the arccosine transformation(Kθ_(n)=+Sin⁻¹(Aah_(n)), see step S76 in FIG. 8).

When the photographic apparatus 1 is rotated (inclined) at an angleKθ_(n) in a counter-clockwise direction viewed from the front, from thefirst vertical orientation (see FIG. 13), the first digital accelerationAah_(n) is +cos(Kθ_(n)) and the second digital acceleration Aav_(n) is−sin(Kθ_(n)).

Therefore, the inclination angle (the third digital displacement angleKθ_(n)) can be calculated by performing an arccosine transformation onthe first digital acceleration Aah_(n) or by performing an arcsinetransformation on the second digital acceleration Aav_(n) and taking thenegative.

However, while the absolute value of the inclination angle (the thirddigital displacement angle Kθ_(n)) is very small, in other words, nearly0, the variation of the sine function is larger than that of the cosinefunction so that the inclination angle is best calculated by using thearcsine transformation rather than the arccosine transformation(Kθ_(n)=−Sin⁻¹(Aav_(n)), see step S73 in FIG. 8).

When the photographic apparatus 1 is rotated (inclined) at an angleKθ_(n) in a counter-clockwise direction viewed from the front, from thesecond horizontal orientation (see FIG. 14), the first digitalacceleration Aah_(n) is −sin(Kθ_(n)) and the second digital accelerationAav_(n) is −cos(Kθ_(n)).

Therefore, the inclination angle (the third digital displacement angleKθ_(n)) can be calculated by performing an arcsine transformation on thefirst digital acceleration Aah_(n) and taking the negative or byperforming an arccosine transformation on the second digitalacceleration Aav_(n) and taking the negative.

However, while the absolute value of the inclination angle (the thirddigital displacement angle Kθ_(n)) is very small, in other words, nearly0, the variation of the sine function is larger than that of the cosinefunction so that the inclination angle is best calculated by using thearcsine transformation rather than the arccosine transformation(Kθ_(n)=−Sin⁻¹(Aah_(n)), see step S77 in FIG. 8).

When the photographic apparatus 1 is rotated (inclined) at an angleKθ_(n) in a counter-clockwise direction viewed from the front, from thesecond vertical orientation (see FIG. 15), the first digitalacceleration Aah_(n) is −cos(Kθ_(n)) and the second digital accelerationAav_(n) is +sin(Kθ_(n)).

Therefore, the inclination angle (the third digital displacement angleKθ_(n)) can be calculated by performing an arccosine transformation onthe first digital acceleration Aah_(n) and taking the negative or byperforming an arcsine transformation on the second digital accelerationAav_(n).

However, while the absolute value of the inclination angle (the thirddigital displacement angle Kθ_(n)) is very small, in other words, isnearly 0, the variation of the sine function is larger than that of thecosine function so that the inclination angle is best calculated byusing the arcsine transformation rather than the arccosinetransformation (Kθ_(n)=+Sin⁻¹(Aav_(n)), see step S74 in FIG. 8).

When the front surface of the photographic apparatus 1 faces mostlyupward or downward, the first digital acceleration Aah_(n) and thesecond digital acceleration Aav_(n) are nearly 0. In this case, thismeans that inclination correction, in other words, the rotationalmovement in accordance with the inclination angle, is not necessary, itis desirable to perform the stabilization and inclination correctionwith the inclination angle being minimal.

However, when the arccosine transformation on the first digitalacceleration Aah_(n) or the second digital acceleration Aav_(n) that isnearly 0 is performed, the absolute value of the inclination angle (thethird digital displacement angle Kθ_(n)) is a large value. In this case,the stabilization and inclination correction is performed with theinclination angle being large, even when the rotational movement inaccordance with the inclination angle is not necessary. Therefore, theinclination correction cannot be performed correctly.

Therefore, in order to eliminate the inclination angle, it is necessaryto determine whether the front surface of the photographic apparatus 1faces mostly upward or downward using an additional determinationfactor.

An example of the additional determination factor is the determinationof whether the sum of the absolute value of the first digitalacceleration Aah_(n) and the absolute value of the second digitalacceleration Aav_(n) is less than a threshold value.

On the other hand, when the arcsine transformation on the first digitalacceleration Aah_(n) or the second digital acceleration Aav_(n) that isnearly 0 is performed, the absolute value of the inclination angle (thethird digital displacement angle Kθ_(n)) is a small value (nearly 0). Inthis case, the stabilization and inclination correction can beperformed, with the inclination angle being small. Therefore, it is notnecessary to determine whether the front surface of the photographicapparatus 1 faces mostly upward or downward by using the additionaldetermination factor.

Furthermore, in the embodiment, the holding state of the photographicapparatus 1 is specified, on the basis of the magnitude relation betweenthe absolute value of the first digital acceleration Aah_(n) and theabsolute value of the second digital acceleration Aav_(n), and the signof that larger value without applying the absolute value.

Specifically, when the absolute value of the second digital accelerationAav_(n) is greater than or equal to the absolute value of the firstdigital acceleration Aah_(n), and when the second digital accelerationAav_(n) is greater than or equal to 0, it is determined that thephotographic apparatus 1 is held approximately in the first horizontalorientation (SIS=0, see step S96 in FIG. 17).

When the absolute value of the second digital acceleration Aav_(n) isgreater than or equal to the absolute value of the first digitalacceleration Aah_(n), and when the second digital acceleration Aav_(n)is less than 0, it is determined that the photographic apparatus 1 isheld approximately in the second horizontal orientation (SIS=1, see stepS97 in FIG. 17).

Specifically, when the absolute value of the second digital accelerationAav_(n) is less than the absolute value of the first digitalacceleration Aah_(n), and when the first digital acceleration Aah_(n) isgreater than or equal to 0, it is determined that the photographicapparatus 1 is held approximately in the first vertical orientation(SIS=2, see step S93 in FIG. 17).

When the absolute value of the second digital acceleration Aav_(n) isless than the absolute value of the first digital acceleration Aah_(n),and when the first digital acceleration Aah_(n) is less than 0, it isdetermined that the photographic apparatus 1 is held approximately inthe second vertical orientation (SIS=3, see step S94 in FIG. 17).

The value “n” is an integer greater than or equal to 0, and indicatesthe duration in milliseconds from the point when the timer interruptprocess commences, (t=0, and see step S11 in FIG. 4), to when the lastinterrupt process of the timer is performed (t=n).

In the digital high-pass filtering regarding the yaw, the first digitalangular velocity VVx_(n) is calculated by dividing the sum of the firstdigital angular velocity VVx₀ and VVx_(n-1) (calculated by the timerinterrupt process before the 1 ms predetermined time interval, beforethe last timer interrupt process is performed) by the first high-passfilter time constant hx, and then subtracting the resulting quotientfrom the first digital angular velocity signal Vx_(n)(VVx_(n)=Vx_(n)−(ΣVVx_(n-1))÷hx, see (1) in FIG. 6).

In the digital high-pass filtering regarding the pitch, the seconddigital angular velocity VVy_(n) is calculated by dividing the sum ofthe second digital angular velocity VVy₀ and VVy_(n-1) (calculated bythe timer interrupt process before the 1 ms predetermined time interval,before the last timer interrupt process is performed) by the secondhigh-pass filter time constant hy, and then subtracting the resultingquotient from the second digital angular velocity signal Vy_(n)(VVy_(n)=Vy_(n)−(ΣVVy_(n-1))÷hy, see (1) in FIG. 6).

In the integration regarding the yaw, the first digital displacementangle Kθ_(n) is calculated by summing the first digital angular velocityVVx₀ at the point when the timer interrupt process commences, t=0, (seestep S11 in FIG. 4) and the first digital angular velocity VVx_(n) atthe point when the last timer interrupt process is performed (t=n),(Kx_(n)=ΣVVx_(n), see (7) in FIG. 6).

Similarly, in the integration regarding the pitch, the second digitaldisplacement angle Ky_(n) is calculated by summing the second digitalangular velocity VVy₀ at the point when the timer interrupt processcommences and the second digital angular velocity VVy_(n) at the pointwhen the last timer interrupt process is performed (Ky_(n)=ΣVVy_(n), see(7) in FIG. 6).

The inclination angle, in other words, the third digital displacementangle Kθ_(n) is calculated by performing the arcsine transformation onthe smaller of the absolute value of the first digital accelerationAah_(n) and the absolute value of the second digital accelerationAav_(n) and by adding a positive or negative sign(Kθ_(n)=+Sin⁻¹(Aah_(n)), −Sin⁻¹(Aah_(n)), +Sin⁻¹(Aav_(n)), or−Sin⁻¹(Aav_(n)), see (8) in FIG. 6).

Whether the positive or negative sign is added is determined on thebasis of the larger of the absolute value of the first digitalacceleration Aah_(n) and the absolute value of the second digitalacceleration Aav_(n), and the sign of that larger value without applyingthe absolute value (see steps S72 and S75 in FIG. 8).

In the embodiment, the angular velocity and acceleration detectionoperation during the timer interrupt process includes a process in thedetection unit 25 and the input of the first angular velocity vx, thesecond angular velocity vy, the first acceleration ah, and the secondacceleration av from the detection unit 25 to the CPU 21.

In the calculation of the third digital displacement angle Kθ_(n), anintegration is not performed because it is unnecessary. Therefore, theDC offset does not affect the calculation of the third digitaldisplacement angle Kθ_(n), so the inclination angle can be calculatedaccurately.

When the integration including the DC offset is used, the third digitaldisplacement angle Kθ_(n) represents an unspecified value even if theinclination angle is 0. Accordingly, the movable platform 30 a includingthe imager 39 a 1 is rotated (inclined) compared to the initial state inorder to correct the third digital displacement angle Kθ_(n)representing the unspecified value.

Because the displacement of the movable platform 30 a in this case meansthe inclination of the imager 39 a 1, the captured image displayed onthe display 17 is inclined. When the operator sees the inclined image onthe display 17, the operator must visually detect the inclination of thedisplayed image even if the inclination is very small.

However, in the embodiment, because the DC offset does not exist, theinclination of the imager 39 a 1 caused by the DC offset does not exist.

The CPU 21 calculates the position S_(n) where the imaging unit 39 a(the movable platform 30 a) should be moved, in accordance with thehand-shake quantity (the first and second digital displacement anglesKx_(n) and Ky_(n)) and the inclination angle (the third digitaldisplacement angle Kθ_(n)) calculated for the x direction, the ydirection, and the rotational direction, based on the lens coefficient Fand the hall sensor distance coefficient HSD (Sx_(n)=F×tan(Kx_(n)),Sy_(n)=F×tan(Ky_(n)), and Sθ_(n)=HSD÷2×sin(Kθ_(n))). In thiscalculation, both the translational (linear) movement of the movableplatform 30 a in the xy plane and the rotational movement of the movableplatform 30 a in the xy plane are considered.

The horizontal direction component of the position S_(n) is defined asSx_(n), the vertical direction component of the position S_(n) isdefined as Sy_(n), and the rotational (inclination) direction componentof the position S_(n) is defined as Sθ_(n).

The rotation of the movable platform 30 a is performed by applyingdifferent forces in the y direction on a first driving point and asecond driving point on the movable platform 30 a. The movement of themovable platform 30 a in the y direction is performed by applying thesame driving forces in the y direction on the first and second drivingpoints on the movable platform 30 a. The first driving point is thepoint to which a first vertical electro-magnetic force based on thefirst vertical coil 32 a 1 is applied. The second driving point is thepoint to which a second vertical electro-magnetic force based on thesecond vertical coil 32 a 2 is applied. The first driving point is setto a position close to the first vertical hall sensor hv1. The seconddriving point is set to a position close to the second vertical hallsensor hv2.

The first vertical direction component of the first driving pointcorresponding to the position S_(n) is defined as Syl_(n). The secondvertical direction component of the second driving point correspondingto the position S_(n) is defined as Syr_(n).

The first vertical direction component of the first driving point,Syl_(n), and the second vertical direction component of the seconddriving point, Syr_(n), are calculated on the basis of the verticaldirection component of the position S_(n), Sy_(n), and the rotationaldirection component of the position S_(n), Sθ_(n),(Syl_(n)=Sy_(n)+Sθ_(n), Syr_(n)=Sy_(n)−Sθ_(n), see (4) in FIG. 6).

The calculations of the first digital displacement angle Kx_(n), thesecond digital displacement angle Ky_(n), the third digital displacementangle Kθ_(n), the rotational direction component of the position S_(n),Sθ_(n), the horizontal direction component of the position S_(n),Sx_(n), the vertical direction component of the position S_(n), Sy_(n),the first vertical direction component of the first driving point,Syl_(n), and the second vertical direction component of the seconddriving point, Syr_(n) are performed only when the correction parameterSR is set to 1 and during the release-sequence operation (see steps S62to S65 of FIG. 5). The release-sequence operation commences after theshutter release button 13 is fully depressed and the shutter releaseswitch 13 a is set to the ON state, and does not finish until therelease-state parameter RP is set to 0.

When the stabilization and inclination correction is not performed(SR=0) and during the release sequence operation (RP=1), the positionS_(n) (Sx_(n), Syl_(n), Syr_(n)) where the movable platform 30 a shouldbe moved is set to the initial state (see step S61 in FIG. 5,Sx_(n)=Syl_(n)=Syr_(n)=0).

While the release-state parameter RP is set to 0, in other words, exceptfor during the release sequence operation, the calculations of the firstdigital displacement angle Kx_(n), the second digital displacement angleKy_(n), the third digital displacement angle Kθ_(n), the rotationaldirection component of the position S_(n), Sθ_(n), the horizontaldirection component of the position S_(n), Sx_(n), the verticaldirection component of the position S_(n), Sy_(n), the first verticaldirection component of the first driving point, Syl_(n), and the secondvertical direction component of the second driving point, Syr_(n) arenot performed. Therefore, in this case, driving of the movable platform30 a is not performed (see step S58 in FIG. 5).

However, the calculation of the holding state parameter SIS, whichspecifies the holding state of the photographic apparatus 1, isperformed (see step S56 in FIG. 5).

Therefore, in the embodiment, the detection of the gravitationalcomponents for the inclination correction and for specifying the holdingstate of the photographic apparatus 1 can be performed by using the sameacceleration sensor 26 c.

The movement of the movable platform 30 a, which includes the imagingunit 39 a, is performed by using an electro-magnetic force and isdescribed later.

The driving force D_(n) is for driving the driver circuit 29 in order tomove the movable platform 30 a to the position S_(n).

The horizontal direction component of the driving force D_(n) for thefirst and second horizontal coils 31 a 1 and 31 a 2 is defined as thehorizontal driving force Dx_(n) (after D/A conversion, the horizontalPWM duty dx).

The vertical direction component of the driving force D_(n) for thefirst vertical coil 32 a 1 is defined as the first vertical drivingforce Dyl_(n) (after D/A conversion, the first vertical PWM duty dyl).

The vertical direction component of the driving force D_(n) for thesecond vertical coil 32 a 2 is defined as the second vertical drivingforce Dyr_(n) (after D/A conversion, the second vertical PWM duty dyr).

The correction unit 30 is an apparatus that corrects for the effects ofhand shake by moving the imaging unit 39 a to the position S_(n), bycanceling the lag of the subject image on the imaging surface of theimager 39 a 1 of the imaging unit 39 a, and by stabilizing the subjectimage displayed on the imaging surface of the imager 39 a 1.

The correction unit 30 has a fixed unit 30 b and a movable platform 30 athat includes the imaging unit 39 a and can be moved in the xy plane.

By moving the movable platform 30 a in the x direction, the firststabilization for correcting the hand shake caused by yaw, which is thefirst hand-shake displacement angle around the y direction, isperformed; and by moving the movable platform 30 a in the y direction,the second stabilization for correcting the hand shake caused by pitch,which is the second hand-shake displacement angle around the xdirection, is performed (the translational movement).

Moreover, the correction unit 30 performs the inclination correction(the rotational movement) that corrects (reduces) the inclination of thephotographic apparatus 1 formed by rotation of the photographicapparatus 1 around its optical axis LX, as measured with respect to alevel plane perpendicular to the direction of gravitational force, byrotating the movable platform 30 a including the imaging unit 39 aaround an axis parallel to the optical axis LX.

In other words, in the inclination correction, the movement controlrepositions the movable platform 30 a so that the upper and lower sidesof the rectangle composing the outline of the imaging surface of theimager 39 a 1 are perpendicular to the direction of gravitational forceand the left and right sides are parallel to the direction ofgravitational force.

Therefore, the imager 39 a 1 can be automatically leveled without usinga level vial. When the photographic apparatus 1 images a subjectincluding the horizon, the imaging operation can be performed, with theupper and lower sides of the rectangle composing the outline of theimaging surface of the imager 39 a 1 being parallel to the horizon.

Moreover, due to the inclination correction, the upper and lower sidesof the rectangle composing the outline of the imaging surface of theimager 39 a 1 are kept perpendicular to the direction of gravitationalforce, and the left and right sides of the rectangle composing theoutline of the imaging surface of the imager 39 a 1 are kept parallel tothe direction of gravitational force. Therefore, hand shake caused byroll is also corrected by the inclination correction. In other words,rotating the movable platform 30 a in the xy plane for the inclinationcorrection also achieves a third stabilization for correcting the handshake caused by roll.

When the stabilization and inclination correction is not performed(SR=0), in other words, when the photographic apparatus 1 is not in thecorrection mode, the position S_(n) (Sx_(n), Syl_(n), Syr_(n)) where themovable platform 30 a should be moved is set to the predeterminedposition. In the embodiment, the predetermined position is the center ofits movement range.

Driving of the movable platform 30 a, including movement to the fixed(held) position of the initial state, is performed by theelectro-magnetic force of the coil unit and the magnetic unit throughthe driver circuit 29, which has the horizontal PWM duty dx input fromthe PWM 0 of the CPU 21, the first vertical PWM duty dyl input from thePWM 1 of the CPU 21, and the second vertical PWM duty dyr input from thePWM 2 of the CPU 21 (see (6) in FIG. 6).

The detected-position P_(n) of the movable platform 30 a, either beforeor after the movement effected by the driver circuit 29, is detected bythe hall sensor unit 44 a and the hall-sensor signal-processing unit 45.

Information regarding the horizontal direction component of thedetected-position P_(n), in other words, the horizontaldetected-position signal px, is input to the A/D converter A/D 4 of theCPU 21 (see (2) in FIG. 6). The horizontal detected-position signal pxis an analog signal that is converted to a digital signal by the A/Dconverter A/D 4 (A/D conversion operation). The horizontal directioncomponent of the detected-position P_(n) after the A/D conversionoperation, is defined as pdx_(n) and corresponds to the horizontaldetected-position signal px.

Information regarding one of the vertical direction components of thedetected-position P_(n), in other words, the first verticaldetected-position signal pyl, is input to the A/D converter A/D 5 of theCPU 21. The first vertical detected-position signal pyl is an analogsignal that is converted to a digital signal by the A/D converter A/D 5(A/D conversion operation). The first vertical direction component ofthe detected-position P_(n) after the A/D conversion operation isdefined as pdyl_(n) and corresponds to the first verticaldetected-position signal pyl.

Information regarding the other of the vertical direction components ofthe detected-position P_(n), in other words, the second verticaldetected-position signal pyr, is input to the A/D converter A/D 6 of theCPU 21. The second vertical detected-position signal pyr is an analogsignal that is converted to a digital signal by the A/D converter A/D 6(A/D conversion operation). The second vertical direction component ofthe detected-position P_(n) after the A/D conversion operation isdefined as pdyr_(n) and corresponds to the second verticaldetected-position signal pyr.

The PID (Proportional Integral Differential) control calculates thehorizontal driving force Dx_(n) and the first and second verticaldriving forces Dyl_(n) and Dyr_(n) on the basis of the coordinate datafor the detected-position P_(n) (pdx_(n), pdyl_(n), pdyr_(n)) and theposition S_(n) (Sx_(n), Syl_(n), Syr_(n)) following movement (see (5) inFIG. 6).

Driving of the movable platform 30 a to the position S_(n), (Sx_(n),Syl_(n), Syr_(n)) corresponding to the stabilization and inclinationcorrection of the PID control, is performed when the photographicapparatus 1 is in the correction mode (SR=1) where the correction switch14 a is set to the ON state and when the release-state parameter RP isset to 1 (RP=1).

When the correction parameter SR is 0 and the release-state parameter RPis set to 1, PID control unrelated to the stabilization and inclinationcorrection is performed so that the movable platform 30 a is moved tothe predetermined position (the center of the movement range) at theinitial state such that each of the four sides composing the outline ofthe imaging surface of the imager 39 a 1 of the imaging unit 39 a isparallel to either the x direction or the y direction, in other words,such that the movable platform 30 a is not rotated (inclined).

The movable platform 30 a has a coil unit for driving that is comprisedof a first horizontal coil 31 a 1, a second horizontal coil 31 a 2, afirst vertical coil 32 a 1, and a second vertical coil 32 a 2, animaging unit 39 a having the imager 39 a 1, and a hall sensor unit 44 aas a magnetic-field change-detecting element unit (see FIG. 7). In theembodiment, the imager 39 a 1 is a CCD; however, the imager 39 a 1 maybe of another type, such as a CMOS, etc.

The fixed unit 30 b has a magnetic position detection and driving unitthat is comprised of a first horizontal magnet 411 b 1, a secondhorizontal magnet 411 b 2, a first vertical magnet 412 b 1, a secondvertical magnet 412 b 2, a first horizontal yoke 431 b 1, a secondhorizontal yoke 431 b 2, a first vertical yoke 432 b 1, and a secondvertical yoke 432 b 2.

The fixed unit 30 b movably and rotatably supports the movable platform30 a in the rectangular-shaped movement range in the xy plane, usingballs, etc. The balls are arranged between the fixed unit 30 b and themovable platform 30 a.

When the central area of the imager 39 a 1 is intersecting the opticalaxis LX of the camera lens 67, the relationship between the position ofthe movable platform 30 a and the position of the fixed unit 30 b isarranged so that the movable platform 30 a is positioned at the centerof its movement range in both the x direction and the y direction, inorder to utilize the full size of the imaging range of the imager 39 a1.

The rectangular form of the imaging surface of the imager 39 a 1 has twodiagonal lines. In the embodiment, the center of the imager 39 a 1 is atthe intersection of these two diagonal lines.

Furthermore, the movable platform 30 a is positioned at the center ofits movement range in both the x direction and the y direction, and eachof the four sides composing the outline of the imaging surface of theimager 39 a 1 is parallel to either the x direction or the y direction,in the initial state immediately after the shutter release switch 13 ais set to the ON state so that the release sequence operation commences(see step S21 of FIG. 4). Then, the stabilization and inclinationcorrection commences.

The first horizontal coil 31 a 1, the second horizontal coil 31 a 2, thefirst vertical coil 32 a 1, the second vertical coil 32 a 2, and thehall sensor unit 44 a are attached to the movable platform 30 a.

The first horizontal coil 31 a 1 forms a seat and a spiral-shaped coilpattern. The coil pattern of the first horizontal coil 31 a 1 has lineswhich are parallel to the y direction, thus creating the firsthorizontal electro-magnetic force to move the movable platform 30 a thatincludes the first horizontal coil 31 a 1, in the x direction.

The first horizontal electro-magnetic force is created by the currentdirection of the first horizontal coil 31 a 1 and the magnetic-fielddirection of the first horizontal magnet 411 b 1.

The second horizontal coil 31 a 2 forms a seat and a spiral-shaped coilpattern. The coil pattern of the second horizontal coil 31 a 2 has lineswhich are parallel to the y direction, thus creating the secondhorizontal electro-magnetic force to move the movable platform 30 a thatincludes the second horizontal coil 31 a 2, in the x direction.

The second horizontal electro-magnetic force is created by the currentdirection of the second horizontal coil 31 a 2 and the magnetic-fielddirection of the second horizontal magnet 411 b 2.

The first vertical coil 32 a 1 forms a seat and a spiral-shaped coilpattern. The coil pattern of the first vertical coil 32 a 1 has lineswhich are parallel to the x direction, thus creating the first verticalelectro-magnetic force to move the movable platform 30 a that includesthe first vertical coil 32 a 1, in the y direction and to rotate themovable platform 30 a.

The first vertical electro-magnetic force is created by the currentdirection of the first vertical coil 32 a 1 and the magnetic-fielddirection of the first vertical magnet 412 b 1.

The second vertical coil 32 a 2 forms a seat and a spiral-shaped coilpattern. The coil pattern of the second vertical coil 32 a 2 has lineswhich are parallel to the x direction, thus creating the second verticalelectro-magnetic force to move the movable platform 30 a that includesthe second vertical coil 32 a 2, in the y direction and to rotate themovable platform 30 a.

The second vertical electro-magnetic force is created by the currentdirection of the second vertical coil 32 a 2 and the magnetic-fielddirection of the second vertical magnet 412 b 2.

The first and second horizontal coils 31 a 1 and 31 a 2 and the firstand second vertical coils 32 a 1 and 32 a 2 are connected to the drivercircuit 29, which drives the first and second horizontal coils 31 a 1and 31 a 2 and the first and second vertical coils 32 a 1 and 32 a 2,through the flexible circuit board (not depicted).

The horizontal PWM duty dx, that is a duty ratio of a PWM pulse, isinput to the driver circuit 29 from the PWM 0 of the CPU 21. The firstvertical PWM duty dyl, that is a duty ratio of a PWM pulse, is input tothe driver circuit 29 from the PWM 1 of the CPU 21. The second verticalPWM duty dyr, that is a duty ratio of a PWM pulse, is input to thedriver circuit 29 from the PWM 2 of the CPU 21.

The driver circuit 29 supplies the same power to the first and secondhorizontal coils 31 a 1 and 31 a 2, corresponding to the value of thehorizontal PWM duty dx, to move the movable platform 30 a in the xdirection.

The driver circuit 29 supplies power to the first vertical coil 32 a 1corresponding to the value of the first vertical PWM duty dyl and to thesecond vertical coil 32 a 2 corresponding to the value of the secondvertical PWM duty dyr, in order to move the movable platform 30 a in they direction and to rotate the movable platform 30 a.

The positional relationship between the first and second horizontalcoils 31 a 1 and 31 a 2 is determined so that the optical axis LX islocated between the first and second horizontal coils 31 a 1 and 31 a 2in the x direction, in the initial state. In other words, the first andsecond horizontal coils 31 a 1 and 31 a 2 are arranged in a symmetricalarrangement centered on the optical axis LX, in the x direction in theinitial state.

The first and second vertical coils 32 a 1 and 32 a 2 are arranged inthe x direction in the initial state.

The first and second horizontal coils 31 a 1 and 31 a 2 are arrangedsuch that the distance between the central area of the imager 39 a 1 andthe central area of the first horizontal coil 31 a 1 in the x directionis the same as the distance between the center of the imager 39 a 1 andthe central area of the second horizontal coil 31 a 2 in the xdirection.

The first and second vertical coils 32 a 1 and 32 a 2 are arranged suchthat in the initial state, the distance between the central area of theimager 39 a 1 and the central area of the first vertical coil 32 a 1 inthe y direction is the same as the distance between the center of theimager 39 a 1 and the central area of the second vertical coil 32 a 2 inthe y direction.

The first horizontal magnet 411 b 1 is attached to the movable platformside of the fixed unit 30 b, where the first horizontal magnet 411 b 1faces the first horizontal coil 31 a 1 and the horizontal hall sensorhh10 in the z direction.

The second horizontal magnet 411 b 2 is attached to the movable platformside of the fixed unit 30 b, where the second horizontal magnet 411 b 2faces the second horizontal coil 31 a 2 in the z direction.

The first vertical magnet 412 b 1 is attached to the movable platformside of the fixed unit 30 b, where the first vertical magnet 412 b 1faces the first vertical coil 32 a 1 and the first vertical hall sensorhv1 in the z direction.

The second vertical magnet 412 b 2 is attached to the movable platformside of the fixed unit 30 b, where the second vertical magnet 412 b 2faces the second vertical coil 32 a 2 and the second vertical hallsensor hv2 in the z direction.

The first horizontal magnet 411 b 1 is attached to the first horizontalyoke 431 b 1, such that the N pole and S pole are arranged in the xdirection. The first horizontal yoke 431 b 1 is attached to the fixedunit 30 b.

Likewise, the second horizontal magnet 411 b 2 is attached to the secondhorizontal yoke 431 b 2, such that the N pole and S pole are arranged inthe x direction. The second horizontal yoke 431 b 2 is attached to thefixed unit 30 b.

The first vertical magnet 412 b 1 is attached to the first vertical yoke432 b 1, such that the N pole and S pole are arranged in the ydirection. The first vertical yoke 432 b 1 is attached to the fixed unit30 b.

Likewise, the second vertical magnet 412 b 2 is attached to the secondvertical yoke 432 b 2, such that the N pole and S pole are arranged inthe y direction. The second vertical yoke 432 b 2 is attached to thefixed unit 30 b.

The first and second horizontal yokes 431 b 1 and 431 b 2 are made of asoft magnetic material.

The first horizontal yoke 431 b 1 prevents the magnetic field of thefirst horizontal magnet 411 b 1 from dissipating to the surroundings,and raises the magnetic-flux density between the first horizontal magnet411 b 1 and the first horizontal coil 31 a 1, and between the firsthorizontal magnet 411 b 1 and the horizontal hall sensor hh10.

Similarly, the second horizontal yoke 431 b 2 prevents the magneticfield of the second horizontal magnet 411 b 2 from dissipating to thesurroundings, and raises the magnetic-flux density between the secondhorizontal magnet 411 b 2 and the second horizontal coil 31 a 2.

The first and second vertical yokes 432 b 1 and 432 b 2 are made of asoft magnetic material.

The first vertical yoke 432 b 1 prevents the magnetic field of the firstvertical magnet 412 b 1 from dissipating to the surroundings, and raisesthe magnetic-flux density between the first vertical magnet 412 b 1 andthe first vertical coil 32 a 1, and between the first vertical magnet412 b 1 and the first vertical hall sensor hv1.

Likewise, the second vertical yoke 432 b 2 prevents the magnetic fieldof the second vertical magnet 412 b 2 from dissipating to thesurroundings, and raises the magnetic-flux density between the secondvertical magnet 412 b 2 and the second vertical coil 32 a 2, and betweenthe second vertical magnet 412 b 2 and the second vertical hall sensorhv2.

The first and second horizontal yokes 431 b 1 and 431 b 2 and the firstand second vertical yokes 432 b 1 and 432 b 2 may be composed of onebody or separate bodies.

The hall sensor unit 44 a is a one-axis hall sensor with three componenthall sensors that are electromagnetic converting elements(magnetic-field change-detecting elements) using the Hall Effect. Thehall sensor unit 44 a detects the horizontal detected-position signalpx, the first vertical detected-position signal pyl, and the secondvertical detected-position signal pyr.

One of the three hall sensors is a horizontal hall sensor hh10 fordetecting the horizontal detected-position signal px, and another of thethree hall sensors is a first vertical hall sensor hv1 for detecting thefirst vertical detected-position signal pyl, with the third being asecond vertical hall sensor hv2 for detecting the second verticaldetected-position signal pyr.

The horizontal hall sensor hh10 is attached to the movable platform 30a, where the horizontal hall sensor hh10 faces the first horizontalmagnet 411 b 1 of the fixed unit 30 b in the z direction.

The horizontal hall sensor hh10 may be arranged outside the spiralwinding of the first horizontal coil 31 a 1 in the y direction. However,it is desirable for the horizontal hall sensor hh10 to be arrangedinside the spiral winding of the first horizontal coil 31 a 1, andmidway along the outer circumference of the spiral winding of the firsthorizontal coil 31 a 1 in the x direction (see FIG. 7).

The horizontal hall sensor hh10 is layered on the first horizontal coil31 a 1 in the z direction. Accordingly, the area in which the magneticfield is generated for the position-detecting operation and the area inwhich the magnetic field is generated for driving the movable platform30 a are shared. Therefore, the length of the first horizontal magnet411 b 1 in the y direction and the length of the first horizontal yoke431 b 1 in the y direction can be shortened.

The first vertical hall sensor hv1 is attached to the movable platform30 a, where the first vertical hall sensor hv1 faces the first verticalmagnet 412 b 1 of the fixed unit 30 b in the z direction.

The second vertical hall sensor hv2 is attached to the movable platform30 a, where the second vertical hall sensor hv2 faces the secondvertical magnet 412 b 2 of the fixed unit 30 b in the z direction.

The first and second vertical hall sensors hv1 and hv2 are arranged inthe x direction in the initial state.

The first vertical hall sensor hv1 may be arranged outside the spiralwinding of the first vertical coil 32 a 1 in the x direction. However,it is desirable for the first vertical hall sensor hv1 to be arrangedinside the spiral winding of the first vertical coil 32 a 1, and midwayalong the outer circumference of the spiral winding of the firstvertical coil 32 a 1 in the y direction.

The first vertical hall sensor hv1 is layered on the first vertical coil32 a 1 in the z direction. Accordingly, the area in which the magneticfield is generated for the position-detecting operation and the area inwhich the magnetic field is generated for driving the movable platform30 a are shared. Therefore, the length of the first vertical magnet 412b 1 in the x direction and the length of the first vertical yoke 432 b 1in the x direction can be shortened.

The second vertical hall sensor hv2 may be arranged outside the spiralwinding of the second vertical coil 32 a 2 in the x direction. However,it is desirable for the second vertical hall sensor hv2 to be arrangedinside the spiral winding of the second vertical coil 32 a 2, and midwayalong the outer circumference of the spiral winding of the secondvertical coil 32 a 2 in the y direction.

The second vertical hall sensor hv2 is layered on the second verticalcoil 32 a 2 in the z direction. Accordingly, the area in which themagnetic field is generated for the position-detecting operation and thearea in which the magnetic field is generated for driving the movableplatform 30 a are shared. Therefore, the length of the second verticalmagnet 412 b 2 in the x direction and the length of the second verticalyoke 432 b 2 in the x direction can be shortened.

Furthermore, the first driving point to which the first verticalelectro-magnetic force based on the first vertical coil 32 a 1 isapplied can be close to a position-detecting point by the first verticalhall sensor hv1, and the second driving point to which the secondvertical electro-magnetic force based on the second vertical coil 32 a 2is applied can be close to a position-detecting point by the secondvertical hall sensor hv2. Therefore, accurate driving control of themovable platform 30 a can be performed.

In the initial state, it is desirable for the horizontal hall sensorhh10 to be located at a place on the hall sensor unit 44 a that faces anintermediate area between the N pole and S pole of the first horizontalmagnet 411 b 1 in the x direction, as viewed from the z direction, toperform the position-detecting operation utilizing the full range withinwhich an accurate position-detecting operation can be performed based onthe linear output change (linearity) of the one-axis hall sensor.

Similarly, in the initial state, it is desirable for the first verticalhall sensor hv1 to be located at a place on the hall sensor unit 44 athat faces an intermediate area between the N pole and S pole of thefirst vertical magnet 412 b 1 in the y direction, as viewed from the zdirection.

Likewise, in the initial state, it is desirable for the second verticalhall sensor hv2 to be located at a place on the hall sensor unit 44 athat faces an intermediate area between the N pole and S pole of thesecond vertical magnet 412 b 2 in the y direction, as viewed from the zdirection.

The first hall-sensor signal-processing unit 45 has a signal processingcircuit of the magnetic-field change-detecting element that is comprisedof a first hall-sensor signal-processing circuit 450, a secondhall-sensor signal-processing circuit 460, and a third hall-sensorsignal-processing circuit 470.

The first hall-sensor signal-processing circuit 450 detects a horizontalpotential difference between the output terminals of the horizontal hallsensor hh10, based on the output signal of the horizontal hall sensorhh10.

The first hall-sensor signal-processing circuit 450 outputs thehorizontal detected-position signal px to the A/D converter A/D 4 of theCPU 21, on the basis of the horizontal potential difference. Thehorizontal detected-position signal px represents the location of thepart of the movable platform 30 a which has the horizontal hall sensorhh10, in the x direction.

The first hall-sensor signal-processing circuit 450 is connected to thehorizontal hall sensor hh10 through the flexible circuit board (notdepicted).

The second hall-sensor signal-processing circuit 460 detects a firstvertical potential difference between the output terminals of the firstvertical hall sensor hv1, based on the output signal of the firstvertical hall sensor hv1.

The second hall-sensor signal-processing circuit 460 outputs the firstvertical detected-position signal pyl to the A/D converter A/D 5 of theCPU 21, on the basis of the first vertical potential difference. Thefirst vertical detected-position signal pyl represents the location ofthe part of the movable platform 30 a which has the first vertical hallsensor hv1 (the position-detecting point by the first vertical hallsensor hv1), in the y direction.

The second hall-sensor signal-processing circuit 460 is connected to thefirst vertical hall sensor hv1 through the flexible circuit board (notdepicted).

The third hall-sensor signal-processing circuit 470 detects a secondvertical potential difference between the output terminals of the secondvertical hall sensor hv2, based on the output signal of the secondvertical hall sensor hv2.

The third hall-sensor signal-processing circuit 470 outputs the secondvertical detected-position signal pyr to the A/D converter A/D 6 of theCPU 21, on the basis of the second vertical potential difference. Thesecond vertical detected-position signal pyr represents the location ofthe part of the movable platform 30 a which has the second vertical hallsensor hv2 (the position-detecting point by the second vertical hallsensor hv2), in the y direction.

The third hall-sensor signal-processing circuit 470 is connected to thesecond vertical hall sensor hv2 through the flexible circuit board (notdepicted).

In the embodiment, the three hall sensors (hh10, hv1 and hv2) are usedfor specifying the location of the movable platform 30 a including therotational (inclination) angle.

The locations in the y direction of the two points on the movableplatform 30 a are determined by using two of the three hall sensors (hv1and hv2). The location in the x direction of the one point on themovable platform 30 a is determined by using another of the three hallsensors (hh10). The location of the movable platform 30 a, whichincludes the rotational (inclination) angle in the xy plane, can bedetermined on the basis of the information regarding the locations inthe x direction of the one point and the location in the y direction ofthe two points.

Next, the main operation of the photographic apparatus 1 in theembodiment is explained using the flowchart of FIG. 4.

When the PON switch 11 a is set to the ON state, the electrical power issupplied to the detection unit 25 so that the detection unit 25 is setto the ON state in step S10.

In step S11, the timer interrupt process at the predetermined timeinterval (1 ms) commences. In step S12, the value of the release-stateparameter RP is set to 0. The details of the timer interrupt process inthe embodiment are explained later using the flowchart of FIG. 5.

In step S13, the value of the holding state parameter SIS is set to 0.

In step S14, it is determined whether the photometric switch 12 a is setto the ON state. When it is determined that the photometric switch 12 ais not set to the ON state, the operation returns to step S13 and theprocess in steps S13 and S14 is repeated. Otherwise, the operationcontinues on to step S15.

In step S15, it is determined whether the correction switch 14 a is setto the ON state. When it is determined that the correction switch 14 ais not set to the ON state, the value of the correction parameter SR isset to 0 in step S16. Otherwise, the value of the correction parameterSR is set to 1 in step S17.

When the photometric switch 12 a is set to the ON state, the AE sensorof the AE unit 23 is driven, the photometric operation is performed, andthe aperture value and the duration of the exposure operation arecalculated, in step S18.

In step S19, the AF sensor and the lens control circuit of the AF unit24 are driven to perform the AF sensing and focus operations,respectively. Furthermore, the lens information including the lenscoefficient F is communicated from the camera lens 67 to the CPU 21.

In the photometric operation and the AF sensing operation, the result ofthe calculation of the holding state parameter SIS, which is performedin the timer interrupt process, is used (see step S56 in FIG. 5).

In step S20, it is determined whether the shutter release switch 13 a isset to the ON state. When the shutter release switch 13 a is not set tothe ON state, the operation returns to step S13 and the process in stepsS13 to S19 is repeated. Otherwise, the operation continues on to stepS21.

In step S21, the value of the release-state parameter RP is set to 1,and then the release-sequence operation commences, as the initial state.In the initial state, the movable platform 30 a is positioned at thecenter of its movement range in both the x direction and the ydirection, and each of the four sides of the rectangle composing theoutline of the imaging surface of the imager 39 a 1 is parallel toeither the x direction or the y direction.

In step S22, the value of the mirror state parameter MP is set to 1.

In step S23, the mirror-up operation and the aperture closing operationcorresponding to the aperture value that is either preset or calculated,are performed by the mirror-aperture-shutter unit 18.

After the mirror-up operation is finished, the value of the mirror stateparameter MP is set to 0, in step S24. In step S25, the openingoperation of the shutter (the movement of the front curtain of theshutter) commences.

In step S26, the exposure operation, that is, the electric chargeaccumulation of the imager 39 a 1 (CCD etc.), is performed. After theexposure time has elapsed, the closing operation of the shutter (themovement of the rear curtain in the shutter), the mirror-down operation,and the opening operation of the aperture are performed by themirror-aperture-shutter unit 18, in step S27.

In step S28, the value of the release-state parameter RP is set to 0 sothat the photometric switch 12 a and the shutter release switch 13 a areset to the OFF state and the release-sequence operation is finished. Instep S29, the electric charge accumulated in the imager 39 a 1 duringthe exposure time is read. In step S30, the CPU 21 communicates with theDSP 19 so that the image-processing operation is performed based on theelectric charge read from the imager 39 a 1. The image on which theimage-processing operation is performed is stored in the memory of thephotographic apparatus 1. In step S31, the image stored in the memory isdisplayed on the display 17, and the operation then returns to step S13.In other words, the photographic apparatus 1 is returned to a state inwhich the next imaging operation can be performed.

Next, the timer interrupt process in the embodiment, which commences instep S11 in FIG. 4 and is performed at every predetermined time interval(1 ms) independent of the other operations, is explained using theflowchart of FIG. 5.

When the timer interrupt process commences, the first angular velocityvx, which is output from the detection unit 25, is input to the A/Dconverter A/D 0 of the CPU 21 and converted to the first digital angularvelocity signal Vx_(n), in step S51. The second angular velocity vy,which is also output from the detection unit 25, is input to the A/Dconverter A/D 1 of the CPU 21 and converted to the second digitalangular velocity signal Vy_(n) (the angular velocity detectionoperation).

The low frequencies of the first and second digital angular velocitysignals Vx_(n) and Vy_(n) are reduced in the digital high-pass filtering(the first and second digital angular velocities VVx_(n) and VVy_(n),see (1) in FIG. 6).

When the timer interrupt process commences, the Lo signal is output fromport P10 of the CPU 21.

In step S52, the hall sensor unit 44 a detects the position of themovable platform 30 a. The horizontal detected-position signal px andthe first and second vertical detected-position signals pyl and pyr arecalculated by the hall-sensor signal-processing unit 45. The horizontaldetected-position signal px is then input to the A/D converter A/D 4 ofthe CPU 21 and converted to the digital signal pdx_(n), the firstvertical detected-position signal pyl is then input to the A/D converterA/D 5 of the CPU 21 and converted to the digital signal pdyl_(n), andthe second vertical detected-position signal pyr is input to the A/Dconverter A/D 6 of the CPU 21 and also converted to the digital signalpdyr_(n), both of which thus specify the present position P_(n)(pdx_(n), pdyl_(n), pdyr_(n)) of the movable platform 30 a (see (2) inFIG. 6).

In step S53, it is determined whether the value of the release-stateparameter RP is set to 1. When it is determined that the value of therelease-state parameter RP is not set to 1, the operation continues tostep S54, otherwise, the operation proceeds to step S59.

In step S54, the output signal from port P10 of the CPU 21 is changedfrom the Lo signal to the Hi signal.

In step S55, the first acceleration ah, which is also output from thedetection unit 25, is input to the A/D converter A/D 2 of the CPU 21 andconverted to the first digital acceleration signal Dah_(n). Similarly,the second acceleration av, which is also output from the detection unit25, is input to the A/D converter A/D 3 of the CPU 21 and converted tothe second digital acceleration signal Dav_(n) (the accelerationdetection operation).

In the acceleration detection operation in step S55, the firstacceleration ah and the second acceleration av, which are amplified withthe low amplification rate Am2 by the third and fourth amplifiers 28 cand 28 d corresponding to the Hi signal output from port P10 of the CPU21, are input to the CPU 21.

The high frequencies of the first and second digital accelerationsignals Dah_(n) and Dav_(n) are reduced in the digital low-passfiltering (the first and second digital acceleration Aah_(n) andAav_(n), see (1) in FIG. 6).

In step S56, the holding state of the photographic apparatus 1 isspecified, in other words, the calculation of the holding stateparameter SIS is performed. The details of the calculation of theholding state parameter SIS in the embodiment are explained later usingthe flowchart of FIG. 17.

In step S57, the output signal from port P10 of the CPU 21 is changedfrom the Hi signal to the Lo signal.

In step S58, driving the movable platform 30 a is set to the OFF state,in other words, the correction unit 30 is set to a state where thedriving control of the movable platform 30 a is not performed.

In step S59, the first acceleration ah, which is also output from thedetection unit 25, is input to the A/D converter A/D 2 of the CPU 21 andconverted to the first digital acceleration signal Dah_(n). Similarly,the second acceleration av, which is also output from the detection unit25, is input to the A/D converter A/D 3 of the CPU 21 and converted tothe second digital acceleration signal Dav_(n) (the accelerationdetection operation).

In the acceleration detection operation in step S59, the firstacceleration ah and the second acceleration av, which are amplified withthe high amplification rate Am1 by the third and fourth amplifiers 28 cand 28 d corresponding to the Lo signal output from port P10 of the CPU21, are input to the CPU 21.

The high frequencies of the first and second digital accelerationsignals Dah_(n) and Dav_(n) are reduced in the digital low-passfiltering (the first and second digital acceleration Aah_(n) andAav_(n), see (1) in FIG. 6).

In step S60, it is determined whether the value of the correctionparameter SR is 0. When it is determined that the value of thecorrection parameter SR is 0 (SR=0), in other words, that thephotographic apparatus 1 is not in the correction mode, the positionS_(n) (Sx_(n), Syl_(n), Syr_(n)) where the movable platform 30 a shouldbe moved, is set to the initial state (Sx_(n)=Syl_(n)=Syr_(n)=0) in stepS61 (see (4) in FIG. 6).

When it is determined that the value of the correction parameter SR isnot 0 (SR=1), in other words when the photographic apparatus 1 is incorrection mode, the operation continues to step S62, in order toperform the first and second stabilizations.

In step S62, the third digital displacement angle Kθ_(n) is calculatedon the basis of the first and second digital accelerations Aah_(n) andAav_(n) (see (8) in FIG. 6).

The details of the calculation of the third digital displacement angleKθ_(n) in the embodiment are explained later using the flowchart of FIG.8.

In step S63, the rotational (inclination) direction component of theposition S_(n), Sθ_(n), is calculated on the basis of the third digitaldisplacement angle Kθ_(n) and the hall sensor distance coefficient HSD(see (3) in FIG. 6).

In step S64, the first and second digital displacement angles Kx_(n) andKy_(n) are calculated on the basis of the first and second digitalangular velocities VVx_(n) and VVy_(n) (see (7) in FIG. 6).

In step S65, the horizontal direction component of the position S_(n),Sx_(n), and the vertical direction component of the position S_(n),Sy_(n), are calculated on the basis of the first digital displacementangle Kx_(n), the second digital displacement angle Ky_(n), and the lenscoefficient F (see (3) in FIG. 6).

Then, the first vertical direction component of the first driving pointSyl_(n) and the second vertical direction component of the seconddriving point Syr_(n) are calculated on the basis of the verticaldirection component of the position S_(n), Sy_(n), and the rotational(inclination) direction component of the position S_(n), Sθ_(n) (see (4)in FIG. 6).

In step S66, the horizontal driving force Dx_(n) (the horizontal PWMduty dx), the first vertical driving force Dyl_(n) (the first verticalPWM duty dyl), and the second vertical driving force Dyr_(n) (the secondvertical PWM duty dyr) of the driving force D_(n), which moves themovable platform 30 a to the position S_(n), are calculated on the basisof the position S_(n) (Sx_(n), Sy_(n), Sθ_(n)) that was determined instep S61 or step S65, and the present position P_(n) (pdx_(n), pdyl_(n),pdyr_(n)) (see (5) in FIG. 6).

In step S67, the first and second horizontal coils 31 a 1 and 31 a 2 aredriven by applying the horizontal PWM duty dx to the driver circuit 29;the first vertical coil 32 a 1 is driven by applying the first verticalPWM duty dyl to the driver circuit 29; and the second vertical coil 32 a2 is driven by applying the second vertical PWM duty dyr to the drivercircuit 29, so that the movable platform 30 a is moved to position S_(n)(Sx_(n), Sy_(n), Sθ_(n)) (see (6) in FIG. 6).

The process of steps S66 and S67 is an automatic control calculationthat is performed by the PID automatic control for performing general(normal) proportional, integral, and differential calculations.

Next, the calculation of the third digital displacement angle Kθ_(n),which is performed in step S62 in FIG. 5, is explained using theflowchart of FIG. 8.

When the calculation of the third digital displacement angle Kθ_(n)commences, it is determined whether the absolute value of the seconddigital acceleration Aav_(n) is larger than or equal to the absolutevalue of the first digital acceleration Aah_(n), in step S71.

When it is determined that the absolute value of the second digitalacceleration Aav_(n) is larger than or equal to the absolute value ofthe first digital acceleration Aah_(n), the operation proceeds to stepS75, otherwise, the operation continues to step S72.

In step S72, it is determined whether the first digital accelerationAah_(n) is less than 0. When it is determined that the first digitalacceleration Aah_(n) is less than 0, the operation proceeds to step S74,otherwise, the operation continues to step S73.

In step S73, the CPU 21 determines that the photographic apparatus 1 isheld approximately in the first vertical orientation, and calculates theinclination angle (the third digital displacement angle Kθ_(n)) byperforming the arcsine transformation on the second digital accelerationAav_(n) and taking the negative (Kθ_(n)=−Sin⁻¹(Aav_(n))).

In step S74, the CPU 21 determines that the photographic apparatus isheld approximately in the second vertical orientation, and calculatesthe inclination angle (the third digital displacement angle Kθ_(n)) byperforming the arcsine transformation on the second digital accelerationAav_(n) (Kθ_(n)=+Sin⁻¹(Aav_(n))).

In step S75, it is determined whether the second digital accelerationAav_(n) is less than 0. When it is determined that the second digitalacceleration Aav_(n) is less than 0, the operation proceeds to step S77,otherwise, the operation continues to step S76.

In step S76, the CPU 21 determines that the photographic apparatus 1 isheld approximately in the first horizontal orientation, and calculatesthe inclination angle (the third digital displacement angle Kθ_(n)) byperforming the arcsine transformation on the first digital accelerationAah_(n) (Kθ_(n)=+Sin⁻¹(Aah_(n))).

In step S77, the CPU 21 determines that the photographic apparatus isheld approximately in the second horizontal orientation, and calculatesthe inclination angle (the third digital displacement angle Kθ_(n)) byperforming the arcsine transformation on the first digital accelerationAah_(n) and taking the negative (Kθ_(n)=−sin⁻¹(Aah_(n))).

Next, the calculation of the holding state parameter SIS, which isperformed in step S56 in FIG. 5, is explained using the flowchart ofFIG. 17.

When the calculation of the holding state parameter SIS commences, it isdetermined whether the absolute value of the second digital accelerationAav_(n) is larger than or equal to the absolute value of the firstdigital acceleration Aah_(n), in step S91.

When it is determined that the absolute value of the second digitalacceleration Aav_(n) is larger than or equal to the absolute value ofthe first digital acceleration Aah_(n), the operation proceeds to stepS95, otherwise, the operation continues to step S92.

In step S92, it is determined whether the first digital accelerationAah_(n) is less than 0. When it is determined that the first digitalacceleration Aah_(n) is less than 0, the operation proceeds to step S94,otherwise, the operation continues to step S93.

In step S93, the CPU 21 determines that the photographic apparatus 1 isheld approximately in the first vertical orientation, and the value ofthe holding state parameter SIS is set to 2.

In step S94, the CPU 21 determines that the photographic apparatus isheld approximately in the second vertical orientation, and the value ofthe holding state parameter SIS is set to 3.

In step S95, it is determined whether the second digital accelerationAav_(n) is less than 0. When it is determined that the second digitalacceleration Aav_(n) is less than 0, the operation proceeds to step S97,otherwise, the operation continues to step S96.

In step S96, the CPU 21 determines that the photographic apparatus 1 isheld approximately in the first horizontal orientation, and the value ofthe holding state parameter SIS is set to 0.

In step S97, the CPU 21 determines that the photographic apparatus isheld approximately in the second horizontal orientation, and the valueof the holding state parameter SIS is set to 1.

Therefore, the calculation except for during the release sequenceoperation (RP=0) can be simplified, because the accurate inclinationangle for the inclination correction is not calculated.

Furthermore, it is explained that the hall sensor is used for positiondetection as the magnetic-field change-detecting element. However,another detection element, an MI (Magnetic Impedance) sensor such as ahigh-frequency carrier-type magnetic-field sensor, a magneticresonance-type magnetic-field detecting element, or an MR(Magneto-Resistance effect) element may be used for position detectionpurposes. When one of either the MI sensor, the magnetic resonance-typemagnetic-field detecting element, or the MR element is used, theinformation regarding the position of the movable platform can beobtained by detecting the magnetic-field change, similar to using thehall sensor.

Although the embodiment of the present invention has been describedherein with reference to the accompanying drawings, obviously manymodifications and changes may be made by those skilled in this artwithout departing from the scope of the invention.

The present disclosure relates to subject matter contained in JapanesePatent Application No. 2008-095700 (filed on Apr. 2, 2008), which isexpressly incorporated herein by reference, in its entirety.

1. A photographic apparatus comprising: a movable platform which has animager that captures an optical image through a taking lens, and ismovable and rotatable in an xy plane perpendicular to an optical axis ofsaid taking lens; an acceleration sensor that detects a firstgravitational component and a second gravitational component, said firstgravitational component being the component of gravitationalacceleration in the x direction perpendicular to said optical axis, andsaid second gravitational component being the component of gravitationalacceleration in the y direction perpendicular to said optical axis andsaid x direction; and a controller that specifies a holding state ofsaid photographic apparatus, calculates an inclination angle of saidphotographic apparatus formed by rotation of said photographic apparatusaround said optical axis, as measured with respect to a level planeperpendicular to the direction of gravitational force, on the basis ofsaid first gravitational component and said second gravitationalcomponent, and performs a movement control of said movable platform foran inclination correction based on said inclination angle; saidcontroller specifying said holding state before an imaging operation bysaid imager that commences when a shutter release switch is set to theON state, and performing said inclination correction during said imagingoperation.
 2. The photographic apparatus according to claim 1, whereinsaid controller performs said inclination correction with increased thedetection resolution of the A/D conversion of said first and secondgravitational components, and specifies said holding state with saiddetection resolution decreased compared to said detection resolutionused in said inclination correction.
 3. The photographic apparatusaccording to claim 1, wherein said controller performs said inclinationcorrection on the basis of said first and second gravitationalcomponents that are amplified with a high amplification rate, andspecifies said holding state on the basis of said first and secondgravitational components that are amplified with a low amplificationrate lower than said high amplification rate.
 4. The photographicapparatus according to claim 1, wherein information regarding saidholding state is used for at least one of a photometric operation ofsaid photographic apparatus and an AF sensing operation of saidphotographic apparatus.
 5. The photographic apparatus according to claim1, wherein information regarding said holding state is attached to afile storing an image obtained by said imaging operation.
 6. Thephotographic apparatus according to claim 1, wherein said controllerspecifies said holding state and performs said inclination correction,on the basis of a magnitude relation between the absolute value of saidfirst gravitational component and the absolute value of said secondgravitational component.
 7. The photographic apparatus according toclaim 1, wherein said x direction is perpendicular to the direction ofgravitational force and said y direction is parallel to the direction ofgravitational force when said photographic apparatus is heldhorizontally and either an upper surface or a lower surface of saidphotographic apparatus faces upward; and said x direction is parallel tothe direction of gravitational force and said y direction isperpendicular to the direction of gravitational force when saidphotographic apparatus is held vertically and one of either sidesurfaces of said photographic apparatus faces upward.